Investigating the Effect Which Exercise Has On the Pulse Rate.
Investigating the effect which exercise has on the pulse rate
Introduction:
The heart main job is to transport oxygen around the body. The cardiac cycle is the sequence of events during one complete cycle of a heartbeat. This consists of the simultaneous contraction of the two atria, a short pause, then the simultaneous contraction of the two ventricles, followed by a longer pause while the entire heart relaxes. The whole cycle is repeated about 70- 80 times per minute under resting conditions. When the atria contacts, the blood in them enters the two relaxing ventricles, completely filling them. The mitral and tricuspid valves, which were open, now begin to shut, and as they do so, they create vibrations in the heart walls and tendons, causing the first heart sound. The ventricles on contraction push open the pulmonary and aortic valves and eject blood in to he respective vesicles. The closed mitral and tricuspid valves prevent return of blood into the atria during this phrase. As the ventricles start to relax, the aortic and pulmonary valves close to prevent backward flow of blood, and their closure causes the second heart sound. By now, the atria have filled once again and are ready to start contracting to begin the next cardiac cycle.
The heart beat rate is the number of times a minute the lungs inhale and exhale. The rate increases during exercise because the muscles require an increased supply of oxygen and nutrients. At the same time very active muscles produce a greater volume of carbon dioxide, a waste gas that must be removed by the lungs via the blood.
The regulation of the breathing rate is under both voluntary and involuntary control, although a person can only forcibly stop breathing for a limited time. The regulatory system includes the use of chemoreceptors, which can detect levels of carbon dioxide in the blood. High concentrations of carbon dioxide, occurring for example during exercise, stimulate a fast breathing rate.
Aim:
What I am aiming to do is find out he effect which exercise has on the heart beat rate. The job of the heart is to transport oxygen around the body to all the cells, and to repeat the cycle about 60 times per minute.
Variables:
There are three types of variables, which are used in investigations. These are:
* Independent variables
* Dependent variable
* Fixed or controlled variables
Independent Variables:
This is the variable, which I am going to change. There are many independent variables, which I ...
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Aim:
What I am aiming to do is find out he effect which exercise has on the heart beat rate. The job of the heart is to transport oxygen around the body to all the cells, and to repeat the cycle about 60 times per minute.
Variables:
There are three types of variables, which are used in investigations. These are:
* Independent variables
* Dependent variable
* Fixed or controlled variables
Independent Variables:
This is the variable, which I am going to change. There are many independent variables, which I could change in this experiment, for an example:
* Change the exercise
* Use different types of exercise during the experiment
* Change the resting period in between the exercise
* Change the conditions of the experiment.
* Change the amount of time exercised
The independent variable, which I am going to change, is the time of exercise. I have chosen this because it is more effective of getting more accurate results.
Dependent Variable:
The dependent variable is the pu8lse rate. Wee accurately measure how many beats per minute with the digital pulse meter.
Fixed Variables:
For a fair test all, the independent variables must be kept fixed at all the same values, except for the number of minutes exercised for. There are many conditions or variables, which I have to keep the same for a fair test and for accurate results. For example, I will make the same person, do the same exercise, under the same conditions. If I didn't keep these three factors the same, then it wouldn't be a fair test. We have to dot he same exercise under the same conditions because different types of exercise involve the heart rate to be working at different speeds and strengths. For example, if you sprinted for five minutes your muscles would need more oxygen therefore the heart would beat faster, whereas if you jog for five minutes your body doesn't need as much oxygen. The exercise, which I will be doing for this investigation, is a five metre run, with five paces in between. We have measured the five metres to make it more accurate and I will have someone counting how many paces I do per five metres to keep everything accurate.
Safety:
This is basically common sense. You have to be careful doing this experiment because you have to choose a floor surface, which you know you, won't slip over and hurt your head. Asthmatics also have to be careful whilst doing this experiment because it involves heart rate increasing dramatically. Also realistically you can't warm up because then your muscles would be used, so you have to be careful not to over exercise and pull muscles.
Prediction and Scientific reason:
I predict that the rate of respiration will increase as a result of exercise. I think that there will be a gradual increase to begin with, but as the body has to work harder I believe that the heart will increase at a faster rate. When the exercise is complete I think that the heart rate will gradually decrease back to the resting pulse rising.
I also think that a lot of energy will be used up as the exercise takes place, thus resulting in further increase. If the body is unable to continue aerobic respiration, anaerobic respiration will take place. This results in lactic acid being formed. Finally, the CO2 levels would also rise which would also contribute tot he heart rate increasing.
Apparatus:
The apparatus which I we will be using in this investigation are:
* A person doing the exercise
* A stop watch- the make sure that the person does the certain exercise for the certain time which is required.
* A waist strap heart beat monitor- we will be using this to monitor the heart beat rate of the person exercising
* A digital watch- we will be using this to see the heart beat rate of the person exercising and recording the results, which is read from the watch.
Method
This is how we will set up the apparatus and dot he experiment:
* Get a heart beat rate meter, wet the back of it with water.
* Strap it to your waist and move it up so that it is just under your chest.
* Put the watch on your wrist. Put it up to the chest strap to get a reading.
* Check you pulse rate before exercising
* Run for a minute in the allocated space
* Take your pulse rate after a minute.
* Rest, when your heart rate is back tot he starting rate or it has slowed down, exercise for two minutes.
* Do this for five minutes, making sure your heart rate gets back tot he starting rates and then exercise for another minute longer. Make sure that you rest enough between each exercise.
Results:
Minutes
Purse Rate 1
Pulse rate 2
Pulse rate 3
Average
0
09
05
07
07
31
32
29
30.7
2
45
45
44
44.7
3
79
79
77
78.3
4
89
90
87
88.7
5
203
203
201
202.3
These are the results, which I recorded from the experiment. The heart rate is measured by a digital heart rate meter
This is a graph to show the average of the results:
The thick black line shows the trendline.
Conclusion:
The graph shows that the heart rate doesn't increase a huge amount for the first minute but then increased very steeply for most of the rest of the exercise. I would have expected that in the last minute the heart rate not opt increase much at all because the supply of oxygen to the muscles decreased, a lot of energy will be used up as the exercise took place, the body was unable to continue aerobic respiration and anaerobic respiration took place. This would have resulted in lactic acid being produces but I never got these results. If I had done the experiment for another 5 minutes longer then I would have found out the maximum heart rate but I only did the experiment for five minutes maximum. Also I would have found out, the CO levels would have rose which would have contributed tot he heart rate rising. The only pattern which I can see form my results is that, the more I exercised the more oxygen is needed so therefore the more the heart rate increased. This proves that my prediction was right. Also I noticed that my results for resting were very high for not doing anything. This could be because the person which did the exercise wasn't very fir, did not exercise a lot, or was either not feeling very well that day or wasn't happy about something so it made the heart rate a bit uneasy.
Evaluation:
I feel that my results, which I collected, were fairly accurate. I have already pointed out that the person who did the exercise wasn't fit because the first results were a bit high. This does effect my results but after resting results, the exercising results are fairly accurate. I can tell that m results are accurate because they follow a trend. That as exercise increase, so does the heart rate. I had to change my plan because originally I was going to run up and down five stairs but this couldn't be done because if I had fallen down the stairs or tripped. Surprisingly there were no results, which were not within the trend. If I could do the experiment again I would do the exercise times fore longer, so that I would be able to justice the maximum heart rate prediction which I have briefly mentioned.
There are many ways in which I could change the investigation because I could change the independent variables, which I have already said. Overall I say that the experiment went as well as I expected.
Kellie Atkins
Biology sc2
Science investigation
